Formability of AA7075 Sheet in Single Point Incremental Forming

Abstract

This article presents formability analysis of aluminium alloy 7075 thin sheets in single point incremental forming (SPIF) through prediction of forming limit curve (FLC) and maximum formable wall angle. Deformation instability method based on tool-sheet contact and non-contact zones in incremental forming was used for the prediction of limit strains for plane strain and equi-biaxial stretching strain path. FLC of the material was also determined experimentally, after measuring limit strains for deformed sheet through groove test for the process. Further, maximum forming wall angle of the material was determined for deformed sheet in a square pyramid shape. The theoretical limit strains predicted by deformation instability approach were compared to the experimental values. Theoretically, calculated limit strains were observed to be higher for plane strain path but approximately close for equi-biaxial strain path compared to experimental limit strains. The maximum formable wall was found to be 55˚ for the material in the process.